April 12, 2018 - With more advanced equipment and technology, experts like Dr. Sarah
Hambleton from Agriculture and Agri-Food Canada (AAFC) continue to refine our understanding
and knowledge of different plants and fungi. In particular, correctly naming them
can make a big difference when it comes to developing ways to protect crops from
pests and breeding new varieties of crops.
Dr. Hambleton is an expert in identifying fungi, in particular rusts, a common disease
on many crops. Most recently she worked with Dr. Miao Liu, also at AAFC, and researchers
Dr. Lisa Castlebury and her postdoc Dr. Jill Demers from the United States Department
of Agriculture in Beltsville, Maryland, to better understand rusts on switchgrass.
Switchgrass is an important forage, ornamental, and biofuel crop in Canada and the
"Rust fungi cause diseases on switchgrass and I wanted to get a better understanding
of what species of rust were affecting this grass and where they were found across
the country. Historically, we had always believed that switchgrass was infected
by one of two types of rust, but when I received a sample from Ontario for identification,
it looked like neither one of them." - Dr. Sarah Hambleton, Agriculture and Agri-Food
Intrigued, Dr. Hambleton and Dr. Liu visited AAFC's Canadian National Mycological
Herbarium, a historical biological collection of fungi, to help them correctly identify
the sample that was sent to them for identification. They looked for switchgrass,
and closely related grasses, in the herbarium that had been infected by similar
rust. At the same time, their American colleagues were doing similar investigations
at the United States National Fungus Collections (BPI). Some of these grass samples
dated back to the late 1800s.
The scientists compared the physical characteristics like the colour, texture and
spores of the fungi found on the grasses and sequenced DNA to generate barcodes
(taking very short segments of the fungi's genetic material to identify it). They
also looked at how others had described and identified these rusts and grasses in
"What we found was that five species of rust infect switchgrass, rather than only
two as previously believed. Even more interesting is that none of them were the
species that had been most commonly reported, which we found attacks a different
grass called witchgrass," explained Dr. Hambleton.
"You can't accurately control rust if you don't know exactly what you dealing with,"
explains Dr. Hambleton. "My research is really important to making sure that experts
that breed new crops and develop ways to control pests have a good understanding
of the challenges they are working to solve. Precise identification ensures that
future research will be based on the best available information."
Dr. Hambleton and AAFC's network of agriculture experts play a key role in helping
scientists in various disciplines from around the world address the challenges facing
- Switchgrass is an important forage, ornamental, and biofuel crop in Canada and the
United States of America.
- There are five species of rust that infect switchgrass in Canada, rather than only
two as previously believed.
- The Canadian National Mycological Herbarium collection holds over 350,000 fungal
and fungal plant disease specimens which make it the largest fungarium of non-lichenized
fungi in Canada.
- DNA barcodes of species are helping to correctly identify and classify fungi and
other crop pests.